Fire resistant asphalt roofing and method of manufacture



July 6, 1965 F. w. PRICE ETAL 3,193,439

FIRE RESISTANT ASPHALT ROOFING AND METHOD OF MANUFAGTURE Filed June l5, 1961 INVENToRs Forest W. Pr'ce By Henry F. Koopmann @we f Attorneys United States Patent() 3,193,439 ETRE RESISTANT ASPHALT ROFING AND METHOD GF MANUFACTURE Forest W. Price, Berkeley, and Henry F. Koopmann,

Kensington, Calif., assignors to Fibreboard Paper Products Corporation, 'San Francisco, Calif., a corporation of Delaware Fiied .inne 15, 1961, Ser. No. 117,375 Claims. '(Cl. 1651-93) This invention relates to a re resistant asphalt roofing material, and more particularly to an asphalt roofing of improved re resistance.

Conventional asphalt roongs include a felt base which is saturated with asphalt, an asphalt coating above and below the asphalt saturated felt base, and a top layer of mineral surfacing. Such roofings have a long life, excellent resistance to all types of Weather conditions, and they are relatively low in cost. However, they provide only limited protection against fire. When such roofings are exposed to fire, the asphalt coating becomes molten, it catches rire, and begins to flow down the .roof slope. The flow of asphalt exposes fresh asphalt as Well as the felt base to the flame thereby enabling the fire to burn rapidly through the roof.

ln accordance with this invention, an asphalt roong having greatly improved hre resistant properties is provided by a roofing which has an asphalt saturated organic felt base, an asphalt coating layer above the felt base, and glass fiber reinforcing elements in the asphalt coating which inhibit its iiow at elevated temperatures. The use of an asphalt coating in such a rooting which forms a scum when it is subjected to lire provides an amazing increase in the fire resistance of the roofing. This roofing material may be employed either in the form of shingles or roll roofing.

The glass bers tend to immobilize the upper asphalt coating when it is subjected to re and thus greatly irnprove the lire resistant properties of the roong. The combination of the glass fiber reinforcement hereof with an asphalt coating which forms Va scum when it is subjected to fire provides surprising improvement in fire resistance even compared to a roofing which has either the glass liber reinforcement or scum forming asphalt, but not both. When the rooting which includes the scum forming asphalt is subjected to a flame, the upper part of ythe asphalt coating forms a scum which provides an insulating barrier between the dame and the remainder of the asphalt coating, as well as the saturated felt below the scum. The glass liber reinforcement immobilizes the scum and keeps it from sliding away down the roof. If the scum is permitted to slide away and expose fresh asphalt, the fire burns succeeding layers of freshly exposed asphalt and the saturated felt base until the re burns through the rooting or spreads over a wide area. However, when the scum is retained in place, the coking effect of the re on the exposed stationary scum prevents the re from being fed by the underlying roofing.

Glass fibers are employed to immobilize the asphalt coating layer since they do not burn away when subjected to heat or llame. Furthermore, the glass ber reinforcement is employed in the form of an open textured layer, as hereinafter defined, yand the glass fibers thus act as anchors and reinforcement to hold the coked insulating scum layer in place.

The roong of this invention has a long life like conventional asphalt rooiings since the saturated felt base serves as a reservoir of oily constituents which keep the roofing pliable for many years. The organic felt base gives wind and weather tear resistance, and resistance to failure caused by iiexing not obtainable through the use of glass fiber and asphalt combinations alone. In addi- ICC tion, thefelt base serves as a barrier which prevents the molten asphalt from running out through the bottom of the roofing when exposed to lire. Thus the glass fiber reinforcement and the felt base each serve different but essential purposes in the asphalt rooting of this invention.

In the drawings:

FIG. l is an enlarged fragmentary view of one of .the many possible roofing variations embodying the principles of this invention, with a part of the upper asphalt coating broken away to expose the glass fiber reinforcement, and which for purposes of clarity is more or less schematic in illustrating the relative thicknesses of the various layers.

FIG. 2 is a schematic illustration of the method and apparatus which may be employed to manufacture the roofing of this invention. Y

FIG. 3 is a perspective view of a preferred section of the rooting hereof in which the roofing is in the form of shingles.

In greater detail and with particular reference to FIG. 1, the rooting has an asphalt saturated felt base or layer 2, an upper asphalt coating 3, a continuous open textured layer of glass fibers 4 within the upper asphalt coating 3, a top coating of mineral granules or other suitable mineral surfacing 5, and a bottom asphalt coating 6.

Any conventional felt base used in the roofing field may be employed in the roofing hereof. Such felt bases or foundation layers are generally composed of organ-ic fiber stock, such as vegetable, animal and synthetic fibers. A felt which weighs between about 1 and 30 pounds per hundred pounds of roofing, or in other words which is between about l and 30 percent by weight of the roofing, provides best results. if the felt base is below about 1 percent by weight of Vthe rooting, the roofing loses much of its durability since the felt serves as the reservoir for the asphalt saturant constituents which keep the roof pliable. On the other hand, if the felt is more than about 30 percent by Weight of the rooting, the character of the felt is no longer smooth and its contains clots of fibers. This heavy type of felt cracks easily and causes a substantial reduction in the extent to which the roofing may be flexed without breakage.

A As previously mentioned, the felt base adds to the desired fireproong qualities of the rooting, since in case of lire it restrains the molten upper layer of asphalt coating from running through the roofing material. In other words, the felt aids the glass liber layer in immobilizing the asphalt coating mass in place when the roofing has been subjected to fire.

Any suitable asphalt saturant may be employed to saturate the felt base. Such saturants are conventionally used in roolings to waterproof the felt and provide a reservoir of plasticizing constituents which give the roofingl a long life. The asphalt saturant is generally prepared by air blowing an asphalt having a lsoftening point between 50 F. and 110 F. until it has a softening point of between about F. and 145 F. as measured by ASTM ring and ball test method D-36, but this procedure is not essential since equivalent asphaltic materials may be employed.

Between about 1 and 50 percent by weight of the roofing hereof is composed of asphalt saturant. If the amount of saturant is substantially below about 1 percent by weight of the roofing, it is insufficient to adequately waterproof the felt and provide a roofing of long life. If too much saturant is employed so that it exceeds about 50 percent by weight of the roofing, the felt is unable to ab sorb all of the saturant and the excess saturant tends to bleed into and modify the harder asphalt coating. This causes the asphalt coating to soften under the heat of the sun. Also, an excess of asphalt saturant may exude through the bottom of the rooting at the usual temperateristic of Aforming a scum when it is subjected' to a ame' provides surprising lire resistant properties to the rooting. In the usual asphalt which does n otinherently havescum on the belt'base.

forming property, ithas been found that theinclusion of v the scum forming characteristic, the asphalt coating is desirably formed by air blowing the asphalt together with the Friedel-Crafts catalyst. For example, the catalyst mineral stabilizer. A'range offrom about 0.2 percent to'0.9 percent by weight of Friedel-Crafts catalyst isoptimum and provides best results in providing the desired scum' on the asphalt coating when it is subjected to a re.

The stabilized upper asphaltcoating containing the ground mineral comprises between about and90 percent byweight of theroofing. No additional improvements are obtained when the weight of the upper asphalt coating is increased to more than about 90 percent by weight of the roong. If the roofing contains less than 15 percent by weight of the mineral stabilized upper asphalt coating, there is notenough of the coating material may be added to the commercial asphalt which generally has a softening point of between about 50F. and 110 F. as determined by ASTM ring and ball test method D-36. This asphalt mixture is air blown at a temperature between about 380 F. and 650 F., and the blowing iscontinued until the asphalt has a softening point by the Ring and Ball method of between about 180 F. andY 250 F. Other equivalent means of providing scum-forming properties may be employed such as adding the catalyst to previously blown coating. Generally, if the coating has a softening point of less than 180 F., it is so sott that it tends to melt under the sun. Asphalt coatings which have a softening point above about250 F. are too brittle and tend to crack when exed. y

A finely ground mineral stabilizer is usually incorporated in the upper asphalt coating in order to stabilize the coating when it is subjected to heat or tire and also to improve durability ofthe roong. Suitable stabilizers include ground limestone, feldspar and mica as well as many others well known to those familiar withvthe art. The amount of stabilizer in the coating may vary widely from about zero to about 70 percent by weight of the total weight of asphalt and stabilizer inthe coating. For best results, about 45 to 55 percent by weight of the coating should be composed of the mineral stabilizer. The mineral stabilizer in the coating usually raises the softening point of the asphalt between about 2 F. and 25 F.

In addition the mineral stabilizer usually decreases lthe penetration of the asphalt coating as determined by ASTM test D-5. The asphalt withoutthe stabilizer has a penetration of between about 13 and 25, whereas the mineral stabilized asphalt coating has a penetration of be- Y tween about 10 and 23. These penetration figures for the asphalt coating layer are to be contrasted with the pene,-

Y Y Viscosity, Oentipoises Temperature, F.V

' Saturant Coating,

The Vamount of ferrie chloride or other Friedel-Crafts catalyst employed in the upper asphalt coating may varyV anywhere from between'about V0.1 and about 10.0 percent by weghtbased on theweight of the asphalt withoutthe Y anchor the scum.

to provide a continuous effective protecting coating. Fur thermore, the top layer of mineral granules do not adhere to a very thin coating layer, and thus the roofing becomes impractical when the coating is less than about 15 parts by weight of the roofing. f

An Y open-textured. substantially continuous discrete layer of glass berreinforcement is located in the upper asphalt coating. in this connection, the glass fiber reinforcement maybe entirelywithin the asphalt coating or it may be adhered to. the asphalt saturated felt Vbase by `the top coating or it may be adhered to the top surface of the upper asphalt coating. i These glass fiber reinforcements perform the important function of retaining and irnmobilizing the asphalt .vhenrthe roofing is subjected to re. As previously described, the rooting is particularly resistant to `fire when the glass ber reinforcement is used to immobilize asphalt of the type which is formed into a scum' Vby fire. The open texture of the glass ber reinforcement is of great value in retaining the scum in place, and preventing it from sliding down thel roof. Furthermore, the use of glass' fiber reinforcement insures that the fire will not burn through the roofing. It is not necessary that the entire roofing contain the glass fiber reinforcement, but it is important that the portion of the roong which is exposed in an installed rooting have the opentextured glass fiber vreinforcement layer defined herein in order to immobilize the asphalt coating;

Thus when the rooting is subjected to tire and the scum is formed, the open-textured layer of glass fibers irnmobilizes the scum, and the immobilized scum serves as an insulating layer for the lower portions of the shingle. It is thus apparent that the'roong hereof contains an open-textured glass fiber reinforcement'which is not cornposed of small-loose particles disposed in the asphalt coating that could float away with the molten asphalt, but instead which are anchored in the roong and in turn As used herein, the term open-textured, substantially continuous, layer of glass bers means any arrangement of glass fibers which extends substantially continuously across-the exposedV portion of the roofing element either in substantially continuous interlocking or connected arrangement, or in substantially` continuous strands or elements which are disposed in a layer but which are not necessarily interconnected to each other. Such layer arrangement insures that the glass bers will anchor any localizedarea of asphalt exposed to r'e through the portion of fiber reinforcement anchored in solid asphalt. EX- amples of such Vreinforcement layers which may be employed are commercial prefabricated vglass mats, glass mats formed at the roofing machine, glass ber scrims, porous glass cloth, glass fiber disposed in a random swirl, and longitudinally arranged glass threads. Since the glass fibers disposed in a random swirl and the longitudinally arranged glass threads are-direction in extent, such layers are affixed to the rooting so that the fibers and threads extend across the roofing in a direction generally across the slope of the roof. The random glass fiber swirl and the longitudinally arranged glass threads or strands may be spaced apart and not connected, and yet they form the substantially continuousV layer hereof.

The open-textured layer of glass fiber reinforcement may comprise between nearly zero percent and 3 percent by weight of the weight of the roofing. If the glass ber reinforcement employs threads which are too thin, the threads will not have enough strength and capacity to hold the scum in place when the shingle is subjected to lire. Glass fiber scrims and longitudinal layers of glass iiber threads are effective even when they comprise less than about 0.05 percent and nearly zero percent by weight of the rooting.

The roofing is desirably provided with a top finish that provides coior and texture, and protects the rooting against the action of the sun and the weather. Any suitable finish may be employed, such as conventional mineral granules, sand, and mica. Depending upon the type of finish, it may comprise between about 0.5 percent and 70 percent by weight of the rooting. When large roofing granules are used, the finish may comprise a substantial part of the weight of the finish. Fine sand or dusting applied as a linish is an exampleV of a linish that does not .Weigh very much.

A lower protective coating may be applied to the felt. However, this coating is not an important factor in the fire resistance and can be of the type generally used in the industry, can be left off entirely, or can be replaced by other fire resistant sealants without seriously affecting the improved performance of this roong. When such coatings are employed, asphalt coatings are generally used. This lower coating may vary from between about and about 8 percent by weight of the weight of the shingle. if more than about 8 percent by weight of the rooting is composed or" the bottom coating of asphalt, the roofing tends to blister under normal use.

The bottom asphalt coating on the rooting may advantageously be covered with a layer of dust to render the back of the rooting non-tacky, although this is not essential. A ine mineral dust or mica may be employed for this purpose and the amount may vary between 0 percent by weight to about l0 percent by weight of the weight of the roofing material. Y

The range of the components used in the rooting is set forth in the following table:

Dust

A variety of methods may be employed for placing the glass fiber layer in the roofing material and for preparing the roofing. For example, one method of manufacturing the shingle is schematically illustrated in PEG. 2. The felt 7 guided by rollers 8 passes through'an asphalt saturant bath 9 to form the asphalt saturated felt 2 illustrated in FIG. l.

Next, a first application of the upper asphalt coating is made on the saturated felt by asphalt iiowing through applicator 10 although this step is not always necessary. A vertical scraper bar 11 uniformly distributes the asphalt coating on top of the saturated felt base as it passes beneath bar 11.

The glass iber reinforcement in the form of glass mat, reels of thread, glass cloth, or a scrim of glass fibers 12 is unrolled from a roll 13, and deposited on the top of the base to provide the open-textured, continuous layer of glass fibers 4 inthe roofing. Next, when desired, an application of the upper asphalt coating is made on top of glass liber reinforcement 12 through applicator 1'4 so that the asphalt coating 3 will be above and below the glass liber layer in the roofing. This application of asphalt coating is metered and evenly distributed by roll 15.

The lower coating of asphalt 6 may be applied to the 6 felt by applicator roll 16 which has its bottom portion in coating bath 17. As the rooting passes over roll 15, the roll rotates and carries the lower coating of asphalt to the bottom of the saturated felt base 2.

As the rooting travels onward, the top layer of mineral surfacing 5 is applied on the upper asphalt coating from hopper 18. Ribbed distribution roll 19 provides a uniform layer of mineral surfacing 5 on the rooting. In accordance with the method of this particular example, dust is applied to the back of the rooting by means of hopper 21 and ribbed distribution roll 22 as the roofing winds around large guide rolls 20 and 23 to complete formation of the rooting material.

The temperature of asphalt saturant bath 9 is generally between about 350 F. and 600 F., with the average temperature being about 400 F. The temperature of the coating layer asphalt deposited by applicators 10, 1dand 16 may vary between about 300 F. and about 450 F. with theaverage temperature being about 370 F. The temperature of the molten asphalt used to provide coating layers 3 and 6 is relatively low considering the high melting point and viscosity of the asphalt which is employed. A low temperature is desired so that the coatings will be viscous when they are applied and stay at the location on which they are deposited. On the other hand, the saturant temperature is maintained relatively high considering the low melting point of the saturant so that the saturantwill thoroughly saturate and coat all of the felt bers in the felt base 2 of the rooting.

The weight of the rooting prepared in accordance with this invention may elfectively vary between about l5 and about pounds per factory square, which is 108 square feet. A .weight of about 108 pounds per factory square is preferred. If the weight falls substantially below about l5 pounds per factory square of roofing, the roofing becomes too light to be serviceable and durable. On the other hand if the weight is substantially in excess of 140 pounds per factory square of rooting, the rooting material becomes too heavy and provides a load greater than is desirable in most houses.

The resultant ro'ong material may be applied as a roll roofing, or it may be cut up and utilized as shingles of any desirable design. Surprisingly, l2 x 36" strip shingles weighing 108 lbs, per factory square of rooting, have passed the Class A Underwriters tests for fire resistance. In this connection, it is not necessary to employ thek glass ber reinforcement over the entire surface area of the shingles, but only over the area which is exposed when the shingles are laid. The usual saturated felt base asphalt shingles have not been able to even approach passing the Class A first test. Attempts to improve the iire resistance of such shingles have generally involved the addition of expensive and heavy materials, such as vermiculite layers, with or without very heavy layers or addition of asbestos fibers. The substantial amounts of vermiculite and asbestos renders such shingles unduly heavy and restricts their use to very sturdily constructed buildings which can withstand the load.

`A particularly advantageous rooting construction which utilizes the shingle hereof is shown in FIG. 3. In this roofing shingles 2S are employed which are preferably three times as long as their width. A 12 inch by 36 inch shingle has proven to be particularly desirable. These shingles 25 do not have cut-outs, and therefore provide much greater resistance to fire than shingles which contain cut-outs.

The roofing illustrated in FIG. 3 is formed of courses 26, 27, and 28 of rectangular shingles 2S. The shingles 25 as laid on the roof have side edges 29, lower edges 30 and upper edges 31. Lower edges 30 of shingle 25 in course 27 lie intermediate between the upper and lower edges 31 and 30 in underlying course 26. Similarly, lower edges 30 of the shinglesinV course 23 are intermediate between the upper and lower edges of shingles in underlying course 27. In addition the side edges 29 of shingles 25 in each overlying course'are spaced from the side edges'of` the underlying coursef. The effect of this arrangementy is to provide a stepped pattern of shingles.

In a preferred roofing which contains rectangular shin-` .side of the underlying courses preferably by about inches. VThis arrangement provides at least a double thickness of shingles for all areas of theV roofing and spaced 2 inch strips having a triple thickness of shingle.` Y

The following are examples of the preparation of roofings in accordance with the present invention:

Y VExample l `An asphalt saturated organic fiber felt is coated with ferric chloride catalyzed, oxidized, California base petroleum asphalt containing 55 percent mineral ller.

A layer of 0.9 pounds per factory square glass mat is then laminated to the saturated felt Yby thecoating. Standard No. 11 size granules surface the sheet in the conventional manner. The back ofthe sheet is asphalt coated and dusted with mineral surfacing in the usual manner.

The rooting has the following components in percent by weight:

Next shingles are cut fromthe roofing in 12 inch by 36 inch strips, having no tab cut-outs. then laidin rows with ends butting and with a 7 inch overlap for succeeding courses. shingle is about 108 pounds per factory square.

This shingle was tested by the Underwriters Labora- Y toriesV and passed the Class A re resistance tests to qualify for the Class A labeling service. In accordance with the standard procedure in making these tests, this shingle roofing was subjected to the ame exposure test,

Ythe spread-of-flame test and the |burning brand test. For

the flame exposure and burning brand tests a test deck 31/2 feet wide by 41/3 feet long made of kiln-dried white pine lumber, and the shingle roong hereofV was installed on the deck. For the spread-of-flame test, the test deck was constructed in the same manner and covered by the shingles set up in the arrangement shown in FIG. 3, except that the deck was` 31/3 feet wide and 13 feet long.

In all of the tests the decks were subjected to Van air current which flows uniformly over the top structure of the roof covering, and the velocity of the air current was about 12 miles per hour. The decks were inclined during the tests at a slope of 5 inches per horizontal foot.

In the ame exposure test the test deckrwas subjected to a luminous gas flame which uniformly bathed the top surface of the shingles except for the two .upper corners. The flame developed a temperature of about 1,400 F. and the deck below the roofing did not ignite even though the flame was consecutively left on for 2 minutes and off for 2 minutes for 15 test cycles.

In the spread-of-ame test, the gas flame described in the flame exposure test was permitted to be applied continuously for minutes, and the wooden deck below the shingles hereof did not catch fire.

The Class A burning'brand test was also passed by I were then placed on the surface of the test deck and permitted to burn themselves out. Such brands did not cause the underlying deck to catch re, nor did any portion of the roof covering material blow or fall. olf the test deck in the form of flaming or glowing brands in any of the foregoing three tests. The aming in the spread-of-ame tests did not spread beyond 6 feet, and therefore the rooting passed the Class A tests.

Example 2 A roofing is prepared in the manner set forth in Example 1 except that a layer of .9 pound per factory square of glass mat is laminated to the saturated felt by the coating and'covers the exposed 5 inches of the shingle and about 2 inches of the unexposed portion of the shingle. In addition large minus 6 mesh granules are used to surface the sheet. The roofing is cut into shingles in the same mannerA as in Example 1 and applied to a roof by the procedure described in such example. The weight Yof the shingle isv approximately 135 pounds per factory square.

ThisV shingle passes'all Underwriters Class B tests, and

l two out of three Class A tests.

Y invention is prepared by laminating a layer of glass mat saturated felt base.

The shingles are Y The weight of the Y the roong hereof with the shingles arranged as shown in FIG. 3. A grid of 12 inches'square and approximatelyV 3 inches thick made of kiln dried douglas r lumber free Y grams was ignited to burn freely. T he burning brands having aV weight of 0.9 pound per factory square to a The glassy mat'covers the exposed 5 inches of the linal shingle and over 1 inch of the unexposed portion of the shingle.

An upper asphalt coating of Venezuelan high flash oxidized petroleum asphalt is employed for laminating the glass mat to the asphalt saturated fiber base. The asphalt coating contains approximately 55 percent by weight of mineral filler. The coated felt is then surfaced with minus 6 mesh granules. Next the back of the sheet is asphalt coated and dusted with mineral surfacing in the usual manner.V Shingles are cut from the roofing in 12 inch by 36 inch strips having no tab cutouts. The shingles are applied to the roof in courses with ends butting and in a 'stepped arrangement with a 7 inch head lap for succeeding courses.

The weight of the shingle Vis about pounds per factory square. This shingle shows greatly improved lire resistance as compared to a similar shingle which does not contain the glass fiber mat.

' VExample 4 An asphalt saturated organic fiber felt is coated with ferric chloride, catalyzed, oxidized, California base petroleum asphalt containing 55 percent by weight mineral filler. A layer of glass scrim approximately 1/8 inch by 1/sV inch to l inch by 1 inch covering the entire exposed portion of the shingle and most of the unexposed section is laminated to the saturated felt by the surface coating.

`The roofing is completed and formed into shingles in the same mannerV as in Example 1. This roofing also shows a surprising resistance to lire.

Example 5 Y A rooting is prepared using the components and procedure described in Example 1. However, instead of employing a glass mat as the continuous open-textured layer of glass fibers, continuous strands of glass fiber in parallel, straight lines are placed on the saturated felt and adhered to the felt by the surface coating. The strands are present in an amount of 0.01 pound per factory square. Y i This roofing alsoV demonstrates superior resistance to fire, and the glass fiber strandsY immobilize the scum when it is subjected to re.

We claim:

1. A lire resistant asphalt roofing which comprises a felt base of 'organic fibers saturated with arst asphalt, a coating layer abovethe felt base of a second asphalt having a softening point above that of the iirst asphalt and which forms a scum when subjected to lire, and an opentextured substantially continuous layer of glass ibers united to the asphalt coating, said layer of glass bers having substantial apertures therein which extend through said layer of glass fibers and which are filled with asphalt from said asphalt coating layer.

2. A lire resistant asphalt rooing in accordance with claim 1 in which the lirst asphalt has a softening point between about 110 F. and 145 F. and the second asphalt has a softening point between about 180 F. and 250 F.

3. The roong of claim l wherein said asphalt coating layer comprises an air blown asphalt containing a Friedel- Crafts catalyst.

4. The roofing of clairn 1 wherein said asphalt coating layer contains up to 70 percent by weight finely divided mineral stabilizer and from .1-10 percent by weight ferrie chloride catalyst.

5. The rooting of claim 1 wherein said layer of glass bers is a glass fiber mat.

6. The roofing of claim 1 wherein said layer of glass fibers is a glass cloth.

7. The roofing of claim 1 wherein said layer of glass bers is a glass scrim.

S. The rooting of claim 1 wherein said layer of glass fibers is composed of a plurality of spaced strands of glass ber disposed in substantially parallel relationship.

9. The rooting of claim 1 wherein said layer of glass bers is composed of glass liber disposed in a random swirl.

10. A re resistant asphalt rooing which comprises a felt base of organic bers saturated with a first asphalt, an upper coating layer of a second asphalt above the felt base, said second asphalt having a softening point higher than said rst asphalt and containing from about 0.1 to l0 percent by weight ferric chloride based on the weight of asphalt in said upper coating, an open-textured substantially continuous layer of glass bers within the upper coating, and a lower asphalt coating below the felt base, said layer of glass fibers comprising between about 0.0001 and 3 percent by Weight of said rooting, and having substantial apertures therein which extend through said layer of glass bers and which are filled with asphalt from said upper asphalt coating layer.

References Cited by the Examiner UNITED STATES PATENTS 1,044,558 11/12 Moeller 154-51 1,801,245 4/ 31 Chamberlain 154-51 1,902,298 3/33 Avery et al 154--51 2,034,522 3/ 36 Loetscher.

2,718,479 9/ 55 Bierly.

2,734,827 2/56 Hooks.

2,771,387 11/56 Kleist et al. 161-202 EARL M. BERGERT, Primary Examiner. 

1. A FIRE RESISTANT ASPHALT ROOFING WHICH COMPRISES A FEEL BASE OF ORGANIC FIBERS SATURATED WITH A FIRST ASPHALT, A COATING LAYER ABOVE THE FELT BASE OF A SECOND ASPHALT HAVING A SOFTENING POINT ABOVE THAT OF THE FIRST ASPHALT AND WHICH FORMS A SCUM WHEN SUBJECTED TO FIRE, AND AN OPENTEXTURED SUBSTANTIALLY CONTINUOUS LAYER OF GLASS FIBERS UNITED TO THE ASPHALT COATING, SAID LAYER OF GLASS FIBERS HAVING SUBSTANTIAL APERTURES THEREIN WHICH EXTEND THROUGH SAID LAYER OF GLASS FIBERS AND WHICH ARE FILLED WITH ASPHALT FROM SAID ASPHALT COATING LAYER. 